Hey y'all, I ran across this article the other day and figured I would share it here... I usually use the polarized glasses in the sun light, but here is a visual on how to check your glass for temper.

I believe it more so means that you shouldn't drill it because it is more likely to crack?

__________________"Now if you'll excuse me, I'm going to go on an overnight drunk, and in 10 days I'm going to set out to find the shark that ate my friend and destroy it. Anyone who wants to tag along is more than welcome."

Slight correction.
Annealed glass is not hardened glass and most certainly can be drilled. Annealing is a process in which the glass is made workable for cutting, drilling etc. glass that has not been annealed would be very unstable to shock, temp changes etc.
However you are correct, tempered glass can not be drilled.
Just thought I'd let you know.

So, if I have a Tetra/Aqueon 40 breeder that I just purchased at the Petco $1 a gallon sale that has a "tempered glass" tag on the bottom, are the front, back and sides non-tempered then? I was looking on their site but couldn't find any info about it. I'd like to drill the back for a coast to coast style overflow. If anyone knows, I would really appreciate it. Thanks.

__________________"Everybody seems to know that calcium carbonate is a phosphate binder except for those in the SW hobby" GeoffThere are 10 kinds of people, those that understand base 2 and those that don't.Slow down and enjoy the journey - John Elway to Peyton Manning.Cooking Rock | Randy

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